Procedure and device for the production of a plasma
View Patent ↗The present invention concerns a procedure for the production of a plasma that is at least co-produced in the vacuum chamber ( 1 a ) of a vacuum recipient ( 1 ) of a device suitable for plasma processing with at least one induction coil ( 2 ) carrying an alternating current, where the gas used to produce the plasma is fed into the vacuum chamber ( 1 a ) through at least one inlet ( 3 ) and the vacuum chamber ( 1 a ) is subject to the pumping action of at least one pump arrangement ( 4 ), and where a possibly pulsed direct current is also applied to the induction coil ( 2 ) in order to influence the plasma density.
1. A device for a production of a plasma that comprises:
a vacuum chamber ( 1 a ) of a vacuum recipient ( 1 ); and
at least one induction coil ( 2 ) for at least co-producing the plasma in said vacuum chamber ( 1 a ); and wherein
the vacuum chamber ( 1 a ) comprises:
at least one inlet ( 3 ) to admit a gas serving for the production of the plasma,
at least one pump arrangement ( 4 ),
a substrate table ( 8 ), and
a dark space screening, established as a grounded surface placed at less than a dark space distance from an electrode surface to prevent a glow discharge between the two surfaces,
the induction coil ( 2 ) is connected to an alternating current and a direct current,
the direct current is continuously applied during a plasma processing simultaneously with said alternating current to the induction coil ( 2 ) in order to influence a plasma density,
said induction coil ( 2 ) is separated by means of a dielectric inner casing ( 7 ) or a dielectric window from at least a part of the vacuum recipient ( 1 a ) in which the plasma is produced,
the alternating current is produced by a high frequency generator ( 6 ) operating at a frequency between 100 and 14,000 kHz,
the substrate table ( 8 ) is provided for a substrate ( 9 ),
the substrate table ( 8 ) is formed by an electrode ( 5 a ),
the dark space screening is used as a counter-electrode ( 5 b ), wherein said electrode and said counter-electrode form a pair of electrodes and
wherein, the plasma is co-produced or co-exited by an electric voltage applied to said pair of electrodes ( 5 a ), ( 5 b ) separated by said dark space distance.
2. The device in accordance with claim 1 , wherein the induction coil ( 2 ) is connected to an alternating voltage generator ( 6 ) through an adapter filter ( 12 ) and to a direct voltage generator ( 6 ′) through a low-pass filter ( 13 ).
3. The device according to claim 1 , wherein the electric voltage is an alternating voltage having a frequency of at least 1 MHz.
4. The device according to claim 1 , wherein the electric voltage is a direct voltage pulsed in a unipolar or bipolar manner.
5. The device for the production of a plasma according to claim 1 , wherein the gas is selected from the group consisting of argon, inert gases, chlorine, silicone tetrachloride, boron dichloride, carbon-tetra fluoride, tri-fluoride methane, sulfur hexafluoride, oxygen, methane, silicon hydride, ammonia, nitrogen and hydrogen.
6. The device for the production of a plasma according to claim 1 , wherein the induction coil is of a form selected from the group consisting of flat, pancake and planar coils.
7. The device for the production of a plasma according to claim 1 , wherein said device is used in a vapor deposition apparatus.
8. The device for the production of a plasma according to claim 1 , wherein said substrate table is circular, said dark space screening is ring shaped and said ring shaped dark space screening is fixed to and centered on said circular substrate table by a ring shaped insulator.