CN1140161C

CN1140161C - Microwave plasma source

Info

Publication number: CN1140161C
Application number: CNB001362623A
Authority: CN
Inventors: 武洪臣
Original assignee: BEIJING AERONAUTICS RESEARCH INST
Current assignee: BEIJING AERONAUTICS RESEARCH INST
Priority date: 2000-12-26
Filing date: 2000-12-26
Publication date: 2004-02-25
Anticipated expiration: 2020-12-26
Also published as: CN1317924A

Abstract

The present invention relates to a plasma source for ion implantation surface modification, plasma reinforced deposition and ion nitrification. With vacuum bent waveguide, an iron core is filled in a space between a coil inner cavity and the waveguide, an iron core cover is added at one side end of the coil waveguide, and guide magnetic strips are arranged on coil periphery. Owing to the vacuum bent waveguide, the present invention structurally avoids the high-energy ion bombardment and deposited film layers of a window, the operation time of the window is increased from 3 to 4 hours to long-term continuous work basically without deposit. With the iron core and a magnetic path, the working current of the coil is greatly reduced, and the heat generation of the coil is reduced to about 1/4 of an original value.

Description

Microwave plasma source

Technical field: the plasma source that the present invention relates to a kind of ion-implanted surface-modified, plasma-enhanced deposition and ionic nitriding.

Background technology: at present, quite a few is produced widely used its structure of equipment that is used to produce plasma by microwave source.Microwave sees through coupling window through transmission system and reaches resonant cavity, and magnetic field is produced by coil, and the magnetic field power is regulated by coil current, and when magnetic field was enough strong, the ECR effect took place at the 875Gs place in resonant cavity, and the generation plasma also is diffused in the vacuum chamber.This kind structure is because the microwave coupling window is directly too near to vacuum chamber and separating process district, and state of arts has tangible influence even interruption of work to it, and window is subject to the bombardment of high energy particle, causes window to damage; When carrying out plasma-enhanced deposition, window also can be deposited rete simultaneously with workpiece, when rete is metal and compound thereof, will has a strong impact on the transmission of microwave, even all returns, and causes work to interrupt, and the easy to clean not often of the rete on the deposition; Again because this structure adopts is the ordinary straight waveguide, the air pressure of waveguide one side is atmosphere, can not discharge, thereby discharge only occurs in the arc chamber of vacuum atmosphere, be sidelong electricity in waveguide one in addition and also can hinder the diffusion of the further transmission of microwave and plasma to vacuum chamber.In addition, when adding, electromagnetic field reached 875Gs, because overlapping resonant cavity (general＞Φ 100mm) in the coil, its internal diameter can not be too little, so used electric current is generally bigger, about about 100A, so volume is also bigger.

Summary of the invention: the objective of the invention is, make the window rabbit be subjected to the bombardment of high energy particle, be not deposited plated film, reduce coil current.Technical solution of the present invention is, adopts the vacuum waveguide bend, makes quartz window away from arc chamber and process island, and discharge only occurs in resonant cavity one side; Fill iron core in the space between chamber and the waveguide in coil, and install the iron core lid additional in the termination of coil waveguide one side, to block the magnetic line of force to outdiffusion, row puts the magnetic conduction bar in coil periphery, to form the magnetic circuit of opening towards vacuum chamber.

Owing to used the vacuum waveguide bend, make quartz window away from vacuum chamber and process island, and directly quartz window is changed into non-directly to quartz window by arc chamber, avoided window to be subjected to the phenomenon of high-energy ion bombardment and depositional coating from structure, the microwave quartz window has obtained good protection, and the window banging time was brought up to continuous operation for a long time by original 3-4 hour and do not deposit substantially; Again because the present invention has used iron core and magnetic circuit, make the magnetic field configuration at resonant cavity place that asymmetric change take place, resonant cavity one side is strengthened, waveguide one side weakens greatly, the operating current of coil is reduced greatly, dropped to 60-70A by original 120-140A, the heating of coil approximately is reduced to original 1/4.

Description of drawings

Fig. 1 is the prior art constructions schematic diagram;

Fig. 2 is a kind of example structure schematic diagram of the present invention;

Fig. 3 is the schematic diagram of another kind of example structure of the present invention;

The curve chart that Fig. 4 changes for ECR magnetic field configuration among the present invention.

Embodiment: vacuum waveguide bend 8 is connected to microwave coupling window 3, add iron core 10 between coil 5 and the vacuum waveguide bend 8, the periphery of coil 5 installs magnetic conduction bar 11 additional, its termination encapsulation iron core end cap 9, because the magnetic flux density that coil 5 produces is the two ends symmetries, when arc chamber one side produces 875Gs in magnetic field that waveguide one side also will produce 875Gs, iron core (electrical pure iron DT4) is filled in space between coil 5 inner chambers and waveguide, and install iron core lid 9 additional in the termination of coil 5 waveguides 8 one sides, to block the magnetic line of force to outdiffusion, 5 peripheral rows put magnetic conduction bar 11 at coil, to form the magnetic circuit of opening towards vacuum chamber; Add electric current and the relation that produces magnetic field by measuring, just can be under suitable electric current (general than no iron core time reduction a lot) guarantee to discharge and in waveguide, do not take place.Because the magnetic permeability maximum of electrical pure iron DT4 can reach μ=200000, be far longer than the magnetic permeability of air or vacuum, so coil passes through (change of magnetic field configuration as shown in Figure 3) with the magnetic line of force major part around the interior waveguide bend 8 from core interior, and the inboard only remaining faint magnetic field of waveguide is not enough to cause discharge.And add a cover iron core lid 9 at the end face of coil waveguide one side, the magnetic line of force still is limited in the magnetic circuit, only in the space of arc chamber one side owing to be open magnetic circuit, formed the high-intensity magnetic field district, that is region of discharge.

Formation of the present invention as shown in Figure 2, it is by microwave source 1, transmission system 2, microwave coupling window 3, gas is introduced ring 4, coil 5, resonant cavity 6, vacuum chamber 7, vacuum waveguide bend 8, iron core end cap 9, iron core 10 and magnetic conduction bar 11 are formed, the shape of iron core should be filled up the gap between waveguide and the coil inner chamber, like this, magnetic line of force major part in waveguide one side has focused on core interior, magnetic field in the waveguide cavity is very weak, do not discharge to guarantee waveguide inside, the curving angle and can adopt different angles as required of vacuum waveguide bend 8, Fig. 3 provides is the curve chart that the ECR magnetic field configuration of vacuum waveguide bend 8 when being 180 ° changes, as can be seen from the figure do not add iron core and add the change in the magnetic field configuration at resonant cavity place that obtains behind the iron core: resonant cavity one side is strengthened, waveguide one side weakens greatly, and coil current reduces greatly.In actual applications, vacuum waveguide bend 8 uses 90 °, 270 ° or unspecified angle can obtain the phenomenon of avoiding window to be subjected to high-energy ion bombardment and to be deposited rete.

Claims

1. a microwave plasma source is made up of vacuum waveguide bend, quartz window, resonant cavity, it is characterized in that, quartz window is away from vacuum chamber and process island, and discharge occurs in resonant cavity one side; Fill iron core in the space between chamber and the waveguide in coil, and install the iron core lid additional in the termination of coil waveguide one side, to block the magnetic line of force to outdiffusion, row puts the magnetic conduction bar in coil periphery, to form the magnetic circuit of opening towards vacuum chamber.