Cold cathode ion beam deposition apparatus with segregated gas flow

Abstract

A cold cathode closed drift ion source is provided with segregated gas flow. A first gas may be caused to flow through or along a path around a peripheral portion of an anode so as to pass through the electric gap between the anode and cathode. A second gas (different from the first gas) may be caused to flow toward the ion emitting slit, without much of the second gas having to pass through the electric gap(s). If it is desired to utilize a gas which produces insulative material (e.g., an organosilicon gas), this gas may be used as the second gas. Accordingly, insulative material buildup in the electric gap between the anode and cathode may be reduced, and changes in beam chemistry can be achieved without unduly altering ion beam characteristics.

Description

This invention relates to a cold cathode ion beam deposition apparatus with segregated gas flow, and corresponding method. More particularly, this invention relates to a cold cathode ion beam deposition apparatus wherein different gases are caused to flow through different flow channels toward an area of energetic electrons in order to provide a more efficient ion beam deposition apparatus and corresponding method.BACKGROUND OF THE INVENTIONAn ion source is a device that causes gas molecules to be ionized and then focuses, accelerates, and emits the ionized gas molecules and / or atoms in a beam toward a substrate. Such an ion beam may be used for various technical and technological purposes, including but not limited to, cleaning, activation, polishing, etching, and / or deposition of thin film coatings. Exemplary ion sources are disclosed, for example, in U.S. Pat. Nos. 6,037,717; 6,002,208; and 5,656,819, the disclosures of which are all hereby incorporated herein by reference.FIGS. ...

AI Technical Summary

Benefits of technology

Another object of this invention is to provide a segregated gas flow arrangement in the context of a cold cathode ion source in order to reduce the likelihood of undesired insulative material buildups in the electrical gap between the anode and cathode.

Certain embodiments of this invention still further fulfill one or more of the aforesaid needs and / or objects by providing a method of emitting an ion beam toward a substrate, the method comprising the steps of: providing an ion beam source including an anode and a cathode, so that an electrical gap is provided between the anode and cathode; causing a first gas to flow through a first flow area around a periphery of the anode and through the electrical gap toward an aperture or slit defined in the cathode; causing a second gas to flow through a second gas flow channel or aperture defined in a body of the anode and toward the aperture or slit in the cathode: and ionizing at least a portion of at least one of the fast and second gases proximate the aperture or slit in the cathode and causing an ion beam to be directed from the aperture or slit in the cathode toward the substrate.

Problems solved by technology

Unfortunately, certain of the elements in silane gas are insulative in nature (e.g., silicon carbide may be an insulator in certain applications).

This can interfere with gas flow through the gap or slit, or alternatively it can adversely affect the electric field potential between the anode and cathode proximate slit 15.

In either case, operability and / or efficiency of the ion beam source is adversely affected.

In sum, the flow of gas which produces a substantial amount of insulative material buildup in electrical gap 63 on the anode and cathode may be undesirable in certain applications.

This problem is particularly troublesome at high total flow conditions where the beam 53 can undergo a significant discontinuous transition between two operational modes (e.g., high energy / low current and low energy / high current).

Unfortunately, the sources of the '368, '593 and '447 patents primarily relate to thermionic emissive (hot) electron cathodes.

This is undesirable, as cold-cathode sources such as that of the instant invention typically operate at higher voltages and / or lower gas flows.

1 of the '208 patent where it is indicated that such sources are disadvantageous in that they are not suitable for treating large surfaces and / or have low intensity).

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