USRE38358E1 - Cold cathode ion beam deposition apparatus with segregated gas flow - Google Patents

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 INVENTION

An 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. 1 and 2 illustrate a conventional ion source. In particular, FIG. 1 is a side cross-sectional view of an ion beam source with a circular ion beam emitting slit, and FIG. 2 is a corresponding sectional plan view along section line II—II of FIG.1.

FIG. 3 is a sectional plan view similar to FIG. 2, for purposes of illustrating that the FIG. 1 ion beam source may have an oval ion beam emitting slit as opposed to a circular ion beam emitting slit.

Referring to FIGS. 1-3, the ion source includeshollow housing3 made of a magnetoconductive material such as mild steel, which is used as acathode5. Cathode5 includes cylindrical oroval side wall7, a closed or partially closedbottom wall9, and an approximatelyflat top wall11 in which a circular or ovalion emitting slit15 is defined.Ion emitting slit15 includes aninner periphery17 as well as anouter periphery19.

Working gas supply aperture orhole21 is formed inbottom wall9. Flattop wall11 functions as an accelerating electrode. A magnetic system in the form of a cylindricalpermanent magnet23 with poles N and S of opposite polarity is placed insidehousing3 betweenbottom wall9 andtop wall11. The N-pole facesflat top wall11, while the S-pole facesbottom wall9 of the ion source. The purpose of the magnetic system, includingmagnet23 with a closed magnetic circuit formed by themagnet23,cathode5, side wall(s)7, andbottom wall9, is to induce a substantially transverse magnetic field (MF) in an area proximateion emitting slit15.

A circular or oval shapedanode25, electrically connected topositive pole27 ofelectric power source29, is arranged in the interior ofhousing3 so as to at least partially surroundmagnet23 and be approximately concentric therewith.Anode25 may be fixed inside the housing by way of ring31 (e.g., of ceramic).Anode25 defines acentral opening33 therein in whichmagnet23 is located.Negative pole35 ofelectric power source29 is connected to housing3 (and thus to cathode5) generally at37, so that the cathode and housing are grounded (GR).

Located above housing3 (and thus above cathode5) of the ion source of FIGS. 1-3 isvacuum chamber41.Chamber41 includesevacuation port43 that is connected to a source of vacuum (not shown). An object orsubstrate45 to be treated (e.g., coated, etched, cleaned, etc.) is supported withinvacuum chamber41 above ion emitting slit15 (e.g., by gluing it, fastening it, or otherwise supporting it on an insulator block47). Thus,substrate45 can remain electrically and magnetically isolated from the housing ofvacuum chamber41, yet electrically connected vialine49 tonegative pole35 ofpower source29. Since the interior ofhousing3 can communicate with the interior ofvacuum chamber41, all lines that electrically connectpower source29 withanode25 andsubstrate45 may pass into the interior ofhousing3 and/orchamber41 via conventional electrically feed throughdevices51.

The conventional ion beam source of FIGS. 1-3 is intended for the formation of a unilaterally directedtubular ion beam53, flowing in the direction ofarrow55 toward a surface ofsubstrate45.Ion beam53 emitted from the area ofslit15 is in the form of a circle in the FIG. 2 embodiment and in the form of an oval (i.e., race track) in the FIG. 3 embodiment.

The ion beam source of FIGS. 1-3 operates as follows.Vacuum chamber41 is evacuated, and a workinggas57 is fed into the interior ofhousing3 viaaperture21.Power supply29 is activated and an electric field is generated betweenanode25 andcathode5, which accelerateselectrons59 to high energy. Electron collisions with the working gas in or proximate gap orslit15 leads to ionization and a plasma is generated “Plasma” herein means a cloud of gas including ions of a material to be accelerated towardsubstrate45. The plasma expands and fills aregion including slit15. An electric field is produced inslit15, oriented in the direction of arrow55 (substantially perpendicular to the transverse magnetic field) which causes ions to propagate towardsubstrate45. Electrons in the ion acceleration space inslit15 are propelled by the known E x B drift in a closed loop path within the region of crossed electric and magnetic field linesproximate slit15. These circulating electrons contribute to ionization of the working gas, so that the zone of ionizing collisions extends beyond theelectrical gap63 between the anode and cathode and includes the regionproximate slit15.

For purposes of example, consider the situation where asilane gas57 is utilized by the ion source of FIGS. 1-3. The silane gas, including the silane inclusive molecules therein, passes through the gap at63 betweenanode25 andcathode5. Unfortunately, certain of the elements in silane gas are insulative in nature (e.g., silicon carbide may be an insulator in certain applications). Insulating deposits (e.g., silicon carbide) can quickly build up on the respective surfaces ofanode25 and/orcathode5proximate gap63. 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 cathodeproximate slit15. 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 inelectrical gap63 on the anode and cathode may be undesirable in certain applications.

Moreover, electrical performance of the ion source is sensitive to parameters of gases within gap63 (i.e., the electrical gap between theanode25 and cathode5). For example, electrical performance of the source is sensitive to characteristics such as the density of the gas withingap63, the residence time of the gas withingap63, and/or the molecular weight of the gas withingap63. Changes in gas chemistry at gap63 (intentional or unintentional) can alter the characteristics of ion beam53 (e.g., with regard to energy and/or current density). This problem is particularly troublesome at high total flow conditions where thebeam53 can undergo a significant discontinuous transition between two operational modes (e.g., high energy/low current and low energy/high current).

U.S. Pat. Nos. 5,508,368; 5,888,593: and 5,973,447 relate to ion sources, each of these patents being hereby incorporated herein by reference. 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. These advantages of cold-cathode sources translate into the ability to deposit much harder materials more efficiently (e.g., ta-C versus conventional DLC), and/or the need for fewer or less powerful pump(s). Additional problems with conventional ion sources are discussed in U.S. Pat. No. 6,002,208, in the context of the known Kaufman-type source (e.g., see col. 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).

In view of the above, it will be apparent to those skilled in the an that there exists a need for an ion source including a more efficient gas flow design.

SUMMARY OF THE INVENTION

An object of this invention is to provide a cold cathode closed drift ion source including a segregated gas flow system.

Another object of this invention is to provide a cold cathode ion source in which a one gas is caused to flow through the electrical gap between the anode and cathode toward an ion emitting slit, and another gas is caused to flow toward the slit but without much of said another gas passing through the electrical gap between the anode and cathode (i.e., preferably less than 50% of said another gas passes through this electrical gap, more preferably less than about 30%, and most preferably less than about 20%).

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.

Yet another object of this invention is to provide an ion source including a first gas flow path and a second gas flow path; wherein the first gas flow path accommodates the flow of a first gas toward the ion emitting slit and the second path accommodates the flow of a second gas (different from the first gas) toward the ion emitting slit.

Another object of this invention is to fulfill any and/or all of the aforesaid objects and/or needs.

Generally speaking, this invention fulfills any one or more of the aforesaid needs and/or objects by providing an ion beam source capable of emitting an ion beam toward a substrate, the ion beam source comprising:

a cathode;

an anode located at least partially between respective portions of said cathode, said anode including an inner periphery and an outer periphery;

an electrical gap defined between said anode and said cathode;

a magnet for generating a magnetic field proximate an ion emitting aperture defined in said cathode, wherein an ion beam is emitted toward a substrate from an area in or proximate said ion emitting aperture;

at least one first gas flow aperture or channel for enabling a first gas to flow around a periphery of the anode and through said electrical gap toward said ion emitting aperture; and

al least one second gas flow channel or aperture located within a body of said anode between inner and outer peripheries of said anode; said second gas flow channel or aperture for enabling a second gas to flow through said second gas flow channel or aperture toward said ion emitting aperture.

This invention further fulfills any one or more of the aforesaid needs and/or objects by providing An ion beam source capable of emitting an ion beam toward a substrate, the ion beam source comprising:

an anode and a cathode, with an electrical gap defined between said anode and said cathode;

at least one first gas flow aperture or channel for enabling a first gas to flow through said electrical gap toward an aperture or slit in said cathode; and

at least one second gas flow channel or aperture for enabling a second gas to flow through said second gas flow channel or aperture toward said aperture or slit without much of the second gas having to flow through said electrical gap.

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.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic partial cross-sectional view of a conventional cold cathode closed drift ion source.

FIG. 2 is a sectional view taking along section line II of FIG.1.

FIG. 3 is a sectional view similar to that of FIG. 2 alongsection line11, illustrating that the ion source of FIG. 1 may be shaped in an oval manner as opposed to a cylindrical or circular manner.

FIG. 4 is a schematic and partial sectional view of a cold cathode closed drift ion source with segregated gas flow according to an embodiment of this invention.

FIG. 5 is a schematic and partial sectional view of certain portions of the ion source of FIG.4.

FIG. 6 is a schematic and partial sectional view of a cold cathode closed drift ion source with segregated gas flow according to another embodiment of this invention.

FIG. 7 is a top view of the anode and magnet of the FIG. 4-5 embodiment of this invention.

FIG. 8 is a op view of the anode and magnet of another embodiment of this invention, illustrating that a plurality of different flow passages may to provided within the body of the anode.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS OF THIS INVENTION

In the following description, for purposes of explanation and not limitation, specific details are set forth in order to provide an understanding of certain embodiments of the present invention. However, it will apparent to those skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well known devices, gases, fasteners, and other components/systems are omitted so as to not obscure the description of the present invention with unnecessary detail. Referring now more particularly to the accompanying drawings, in which like reference numerals indicate like parts/elements/components/areas throughout the several views.

FIG. 4 is a schematic and partial sectional view of an ion source according to an exemplary embodiment of this invention. The cold cathode closed drift type ion source of FIG. 4 is similar in many respects to that of FIGS. 1-3. Closed loop ion emitting slit15 may be circular, cylindrical, rectangular, triangular, elliptical, or oval in shape according to different embodiments of this invention. Shapes herein are for purposes of example only, and are not intended to be limiting.

The terms “aperture”, “channel” and “slit” are used herein for purposes of convenience are not intended to be limited as to shape or size. For example, an aperture herein may be of any shape or size (e.g., circular, rectangular, triangular, semi-circular, trapezoidal, channel-shaped, slit-shaped, or the like). Thus, a “slit”may be both a slit as well as an aperture herein, as may a channel. Likewise, the term “aperture” as used herein includes simple holes as well as apertures in the form of slit, channels, and the like.

The cold cathode closed drift ion source of FIG. 4 may be utilized in order to ionize gas molecules and then focus them and cause them to be accelerated and emitted as abeam53 toward asubstrate45. This ion beam may be utilized for various technical and technological purposes, including but not limited to, cleaning the substrate, activating something on the substrate, polishing the substrate, etching a portion of the substrate, and/or depositing a thin film coating(s) and/or layer(s) on the substrate.

Anode25 includes a body or main body defining aninner periphery15aand anouter periphery15b. Thus, within the main body of theanode25 is an aperture in whichmagnet23 is located. The body ofanode25 includesgas inlet aperture71 defined therein. The inner and outer peripheries of theanode25 may be circular, oval, elliptical, triangular, rectangular, or otherwise shaped in different embodiments of this invention. The inner and outer peripheries of theanode25 may be concentric in certain embodiments, and non-concentric in other embodiments of this invention.

Referring to FIGS. 4-5 and7, in certain exemplary embodiments of thisinvention anode25 is at a positive potential andcathode5 is either at a grounded or negative potential. This causes active electrons to pass throughelectrical gap63 betweenanode25 andcathode5. Magnetic field (MF) caused at least in part bymagnet23proximate slit15 tends to keep the active electrons proximate the slit so that they can ionize gas in the vicinity of the slit. Gas molecules and/or atoms flowing proximate slit15 (some of which may flow through electric gap63) are thus bombarded byelectrons59 and ionized in a known manner. Because of at least the potential ofanode25, the ions are propelled (i.e., accelerated) outwardly fromslit15 in the form of abeam53 towardsubstrate45.Substrate45 may be grounded as shown in FIG. 4 according to certain embodiments of this invention. In other embodiments of this invention,substrate45 need not be grounded.

The particular magnetic circuit illustrated in the drawings is for purposes of example only, and clearly is not intended to be limiting. The magnet may be positioned as illustrated within the circumference ofanode25, or instead it may be provided at other locations in order to produce the transverse magnetic field inslit15. In other words, there are many different ways of producing the transverse field inslit15. For example, as an alternative to the illustrated embodiments, cylindrical magnets could be embedded in the outer cylindrical housing with all or most of the cylindrical magnets having polarities oriented in approximately the same direction and aligned along the axis of the ion source. Then, the central magnet could be replaced with magneto-conductive material, and a closed circuit (with no or minimal gaps) that connects to bothsurfaces defining slit25 is till obtained.

In accordance with different embodiments of this invention, different gases are caused to flow towardslit15 by way of different flow paths. This is done in order to reduce the likelihood of insulative material buildup inelectric gap63 and/or to render the ion source more efficient in nature.

Referring to FIGS. 4-5, it is possible to utilize two, three or more different types of gas in the source according to different embodiments of this invention. These gases include maintenance gas, chemically reactive gas, and/or depositing gas, or any combination thereof.

In general, depositing gas (e.g., silane, siloxane, acetylene, etc.) is utilized whenever it is desired to deposit a thin film coating or layer(s) onsurface46 ofsubstrate45 where the coating is to include material from the depositing gas. In such a case, molecules of the depositing gas are ionizedproximate slit15 by the active electrons which are contained throughout much of the magnetic field (MF). These ions from the depositing gas are then accelerated outwardly as at least part ofbeam53 toward the substrate and are deposited onsurface46 thereof. In such a manner, thin films may be deposited onsubstrate45, such as diamond-like carbon (DLC) thin films, and the like. Exemplary depositing gases (e.g., C₂H₂and/or TMS) which may be used to deposit DLC and other materials on a substrate are disclosed along with the resulting thin film coatings in U.S. Ser. Nos. 09/303,548, filed May 3, 1999, and 09/442,805, filed Nov. 18, 1999, the disclosures of which are both hereby incorporated herein by reference.

As illustrated in FIG. 5, depositing gas may flow towardslit15 through flow path oraperture71 defined in an otherwise solid portion of the body ofanode25. The location of gas flow aperture orpath71 immediately beneath slit15 enables the depositing gas (which often includes insulative components such as silicon (Si)) to flow directly intoslit15 without much of the gas having to pass through theelectrical gap63 betweenanode25 andcathode5. Thus, in certain embodiments of this invention, preferably less than 50% of the depositing gas passes throughelectrical gap63, more preferably less than about 30%, and most preferably less than about 20%). By reducing the amount of depositing gas (e.g., a hydrocarbon or organosilicon gas that results in buildup of insulative material in the electrical gap63) that flows through theelectrical gap63 between the anode and cathode, the tendency of insulative material(s) from the depositing gas to build up on the anode and/or cathode in the area ofelectric gap63 is reduced. Thus, electrical characteristics ofgap63 can be maintained in a more efficient and easy manner.

Once the molecules of the depositing gas have flowed through flow channel oraperture71 inanode25 and reached the MF area proximate slit15, they are bombarded by active electrons located in the MF proximate the slit and ionized so that they are expelled as at least pact ofion beam53 toward substrate45 (e.g., so that a thin film coating(s) can be deposited on the substrate; where the chemical make-up of such a coating(s) depends on the type of gas(es) used).

Maintenance gas (e.g., argon, krypton or xenon) may be utilized in combination with depositing gas in certain embodiments of this invention. However, as illustrated in FIGS. 4 and 5, all of the maintenance gas need not flow through the same channel oraperture71 as the depositing gas. Instead, much of the maintenance gas (e.g., all of the maintenance gas in certain embodiments; or even only a portion of maintenance gas in other embodiments) flows around the inner and/or outer periphery(ies)15aand/or15bof theanode25 and through one or more of the respective electrical gap(s)63 between theanode25 andcathode5, before reachingslit15. As shown in FIGS. 4-5, maintenance gas may flow through one or both of respective channels or flowpaths73,75 around the inner and/or outer periphery (ies) ofanode25. The provision of this maintenance gas in theelectric gap63 between the anode and cathode defines much of the electrical performance of the ion source (i.e., the maintenance gas is the fuel which runs the plasma generated in the vicinity of the slit). For example, the flow rate of the maintenance gas within electric gap(s)63 determines certain electrical characteristics, e.g., voltage and/or current between the anode/cathode. Depending upon the plasma in the gap(s)63, the current in the gap is translated into a beam current, i.e., a flux of ions expelled outwardly inbeam53 toward the substrate. The higher the current in the gap, the greater the ion flux. Thus, it is important to control the amount of gas in respective electric gap(s)63. As discussed above, control of the amounts of gas ingaps63 may be achieved in part by reducing the likelihood of the buildup of insulative material ingaps63 which may reduce the flow of maintenance gas therethrough. Moreover, it will be appreciated by those skilled in the an that the depositing gas may be changed without having to change the maintenance gas in certain embodiments of this invention, so that the type of coating/layer being deposited on substrate can be changed without having to change significant electrical characteristics of the beam and/or gap.

Accordingly, it can be seen that in many embodiments it may be desirable to utilize a first gas as a depositing gas(es) (e.g., silane, siloxane, silazane, cyclohexane, acetylene, etc.) which produces substantial insulative deposits (e.g., SiC); and a second gas(es) (e.g., argon, xenon, krypton, etc.) as a maintenance gas which will not typically cause much material buildup on the anode or cathode in gap(s)63. Thus, the non-insulative maintenance gas passed through one or more of channels orpaths73,75 may be utilized to control and/or determine the electrical characteristics ofion beam53, while the depositing gas injected through flow path oraperture71 within the anode itself may be utilized to determine which ions are to be expelled inbeam53 for deposition on the surface of substrate45 (it is noted that in certain embodiments of this invention all maintenance gas flows throughchannels73 and/or75 and none throughchannel71; while in other embodiments of this invention dome maintenance gas may flow through71 and/or a portion of depositing gas may flow through channel(s)73,75 in addition to channel71). Thus, in certain embodiments of this invention the depositing gas may be changed and/or adjusted with relative frequency, without having to worry about adversely affecting or undesirably changing the electrical characteristics (e.g., ion energy) of thebeam53.

In short, by injecting the depositing gas through a central portion the body of anode25 (i.e., between the inner andouter peripheries15aand156, respectively, of the anode) beneathslit15 so that much of the depositing gas does not have to pass through the direct electrical gap(s)63 between the anode and cathode, less insulative material deposition on the anode and/or cathode occurs in gap(s)63. Moreover, when it is desired to change the material for a coating and/or layer being deposited onsubstrate45, the depositing gas can be changed without unduly altering the electrical characteristics of the ion beam53 (because the maintenance gas need not be changed). Thus, changes inbeam53 chemistry can be achieved without unduly altering the characteristics of the beam itself.

The reduction of insulative material buildup ingaps63 is of particular importance when producing insulating coatings, such as silicon inclusive diamond-like carbon layers/coatings which are highly electrically insulating. Such insulative deposits on the anode and/or cathode in gap(s)63 can disrupt and/or terminate the inter-electrode plasma (the plasma which generates the beam ions) between the anode and cathode.

As discussed above, the ion source of FIGS. 4-5 and7 may be utilized for purposes other than deposition of coatings and/or layers onsubstrate45. For example, the ion source of FIGS. 4-5 and7 may be utilized to direct anion beam53 towardsubstrate45 in order to etch a portion of the substrate (e.g., glass or plastic substrate), or alternatively may be used to clean a surface of the substrate.

In exemplary etching embodiments of this invention, a chemically reactive gas may be utilized and injected throughflow path71 instead of the aforesaid depositing gas. For example, if it is desired to use the ion source to etch asubstrate45 of plastic material, a maintenance gas of argon may be used in combination with a reactive gas of oxygen. The oxygen would be passed throughflow channel71 in the body of the anode (surrounding the magnet), while the argon would be injected through one or both offlow paths73,75 around the inner and outer peripheries of theanode25. Thus, the oxygen and argon ions mix in the area ofslit15, but many of the oxygen ions which were injected throughaperture71 would not have passed through electric gap(s)63. The mixture of oxygen and argon are ionized by electrons in the MF, and these ions are expelled toward the plastic substrate inbeam53. The oxygen ions of the beam react with the plastic surface of the substrate in order to etch the same. In other embodiments where it is desired to etch the surface of asubstrate45 of glass, argon maintenance gas may be utilized in combination with CF₄and/or O₂reactive gases. In other words, either a depositing gas or a non-depositing reactive gas may be injected throughaperture71 directly into slit15 (in combination with maintenance gases) in different embodiments of this invention.

As shown in FIG. 5, it is also possible to direct depositing gas at81 toward the MF proximate slit15 from a position abovetop wall11 of the cathode, such thattop wall11 is located between this optional source(s)82 andanode25. Introducing depositing gas at81 above thetop wall11 may be used either in combination with injecting depositing gas throughaperture71, or instead of introducing depositing gas throughaperture71. In still further embodiments, the depositing gas being introduced at81 may be used in combination with both a maintenance gas introduced at73,75 and/or reactive gas introduced throughchannel71.

When using source(s)82, the depositing gas introduced at81 is directed toward MF where active electrons are present. These reactive electrons ionize the depositing gas so that the ions thereof may be expelled from the vicinity ofslit15 as at least part ofbeam53 towardsubstrate45 so that they can be deposited onsurface46.

The embodiment of FIGS. 4-5 and7 (see especially FIG. 7) illustrates a single gas flow aperture or slit71 that is provided in the body of the anode around the entire periphery of themagnet23. In other words, aperture or slit71 may be shaped in the form of a racetrack, a circle, an oval, a rectangle, an ellipse, or a triangle surrounding the magnet much like the shape of slit15 (i.e., aperture/slit71 is continuous in nature and surrounds the magnet when viewed from above as in FIG.7). However, in other embodiments of this invention,aperture71 need not be continuous and need not surround the magnet.

For example, refer to the embodiment of FIG. 8 where instead of a singlecontinuous aperture71 surrounding themagnet23, a plurality of different and spaced apartgas flow apertures71 are provided in the body of theanode25 between the inner and outer anode peripheries. Each of the plurality ofdifferent flow apertures71 in the FIG. S embodiment may be in the shape of a circle as shown, or alternatively may be shaped as rectangles, triangles, short slits, curved slits, ovals, ellipses, or the like. Two, three, four, five, six, seven, eight, nine, ten (as illustrated in FIG:8), eleven, or moresuch apertures71 may be provided in the body of theanode25 for gas flow purposes in different embodiments of this invention. Depositing and/or reactive gas(es) may be passed through one or more ofapertures71 in the same manner as discussed above, towardslit15 so as to attain advantages discussed herein.

FIG. 6 illustrates another embodiment of this invention. In the FIG,6 embodiment, maintenance gas (as described above) is injected through gas flow paths orchannels85 so that the maintenance gas flows through one or more ofchannels73,75 around the inner and outer peripheries ofanode25, respectively, towardslit15. In the FIG. 6 embodiment, there is no aperture or hole in the anode for injecting a depositing and/or reactive gas. Thus, for example, depositing gas may be injected at alocation81 through at least one flow path or channel in the side ofvacuum chamber41 abovetop cathode wall11. The depositing gas is directed toward the magnetic field (MF) proximate slit15, so that the depositing gas molecules can be ionized and the resulting ions expelled towardsubstrate45 inbeam53. Again, it is beneficial, especially in the case of depositing gases including insulative materials such as silicon, to introduce the depositing gas at a location such as that in FIG. 6 so that much of the depositing gas does not have to pass through the electric gap(es)63 between the anode and cathode. This reduces the potential of insulative material buildups on the anode and/or cathode in electric gap(s)63 as discussed above.

Once given the above disclosure, many other features, modifications, and improvements will become apparent to the skilled artisan. Such other features, modifications, and improvements are therefore considered to be a part of this invention, the scope of which is to be determined by the following claims and equivalents thereof.

Claims (21)

What is claimed is:

1. An ion beam source with a closed loop ion emitting slit capable of emitting an ion beam toward a substrate, the ion beam source comprising:

a hollow cathode;

an anode located at least partially in a portion of said hollow cathode and spaced from said cathode in a manner so as to form an electrical gap between said anode and said cathode through which electrons flow, said anode including an inner periphery and an outer periphery;

at least one magnet for generating a magnetic field proximate a closed loop slit formed in said cathode, wherein an ion beam is emitted toward a the substrate from an area in or proximate said slit;

a first gas flow aperture or channel located adjacent a periphery of said anode for enabling a first gas to flow around the periphery of the anode and through said electrical gap toward said slit; and

at least one second gas flow channel or aperture located within a body of said anode between said inner and outer peripheries of said anode, said at least one second gas flow channel or aperture for enabling a second gas to flow through said second gas flow channel or aperture toward said slit such that at least a portion of the second gas flowing through said second gas flow channel or aperture reaches said closed loop slit without having to pass through said electrical gap between said anode and said cathode.

2. The ion beam source ofclaim 1, wherein said second gas flow channel or aperture comprises a continuous aperture which surrounds said magnet that is encompassed by said inner periphery of said anode.

3. The ion beam source ofclaim 1, further comprising a plurality of spaced apart ones of said second gas flow channels or apertures located within the body of said anode for enabling the second gas to flow through said plurality of second gas flow channels or apertures toward said slit, wherein said plurality of spaced apart ones of said second gas flow channels or apertures are located within said anode such that at least a portion of the second gas flowing through said plurality of spaced apart ones of said second gas flow channels or apertures reaches said slit without having to pass through said electrical gap between said anode and said cathode.

4. The ion beam source ofclaim 1, wherein said first gas comprises an inert gas and said second gas comprises a depositing gas which produces an insulative material.

5. The ion beam source ofclaim 4, wherein said insulative material produced by said second gas includes silicon (Si).

6. The ion beam source ofclaim 1, wherein each of said slit, said first gas flow aperture or channel, and said second gas flow aperture or channel is closed-loop in shape.

7. The ion beam source ofclaim 6, wherein each of said slit, said first gas flow aperture or channel, and said second gas flow aperture or channel is closed-loop in shape and surrounds said magnet when viewed from above.

8. The ion beam source ofclaim 1, wherein said cathode is a cold cathode.

9. The ion beam source ofclaim 1, wherein said cathode comprises a bottom wall and a top wall; and

wherein another gas source is provided for directing a depositing gas toward a magnetic field (MF) proximate said slit via at least one gas flow aperture or channel located at a position such that said top wall of said cathode is at least partially located between said at least one gas flow aperture or channel and a portion of said anode, so that the first gas and said depositing gas from said another source are directed toward the magnetic field (MF) proximate said slit from opposite sides of said top wall of said cathode.

10. The ion beam source ofclaim 1, wherein said anode is maintained at an electrical charge that is positive relative to an electrical charge at which said cathode is maintained.

11. An ion beam source capable of emitting an ion beam toward a substrate, the ion beam source comprising:

a cathode;

an anode located at least partially between respective portions of said cathode, said anode including an inner periphery and an outer periphery;

an electrical gap defined between said anode and said cathode;

at least one magnet for generating a magnetic field proximate an ion emitting aperture defined in said cathode, wherein an ion beam is emitted toward a the substrate from an area in or proximate said ion emitting aperture;

at least one first gas flow aperture or channel for enabling a first gas to flow around a periphery of the anode and through said electrical gap toward said ion emitting aperture; and

at least one second gas flow channel or aperture located within a body of said anode between inner and outer peripheries of said anode, said second gas flow channel or aperture for enabling a second gas to flow through said second gas flow channel or aperture toward said ion emitting aperture.

12. The ion beam source ofclaim 11, wherein said second gas flow channel or aperture is located at a position within said mode such that much of the second gas flowing through said second gas flow channel or aperture reaches said slit without having to pass through said electrical gap between said anode and said cathode.

13. 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 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 in the cathode; and

ionizing at least a portion of at least one of the first and second gases proximate the aperture in the cathode and causing an ion beam to be directed from the aperture in the cathode toward the substrate.

14. The method ofclaim 13, wherein the second gas flow channel or aperture is located in the anode between an inner periphery of the anode and an outer periphery of the anode.

15. The method ofclaim 13, further comprising the steps of:

causing an inert gas toflow through the first flow area around a periphery of the anode and through the electrical gap toward the aperture defined in the cathode;

causing a depositing gas, including more insulative element material than the first gas, to flow through the second gas flow channel or aperture defined in the body of the anode and toward the aperture in the cathode; and

ionizing at least a portion of the depositing gas proximate the aperture in the cathode and causing an ion beam to be directed from the aperture in the cathode toward the substrate.

16. An ion beam source capable of emitting an ion beam toward a substrate, the ion beam source comprising:

an anode and a cathode, with an electrical gap defined between said anode and said cathode;

at least one first gas flow aperture or channel for enabling a first gas to flow through said electrical gap toward an aperture in said cathode; and

at least one second gas flow channel or aperture for enabling a second gas to flow through said second gas flow channel or aperture toward said aperture in said cathode without much of the second gas having to flow through said electrical gap.

17. An ion beam source capable of emitting an ion beam toward a substrate, the ion beam source comprising:

a cathode;

an anode located proximate an aperture defined in the cathode;

at least one magnet for generating a magnetic field proximate the aperture defined in the cathode, wherein an ion beam is emitted toward the substrate from an area in or proximate the aperture defined in the cathode;

a first gas flow aperture or channel for enabling a maintenance gas to flow by the anode and thereafter into the magnetic field proximate the aperture defined in the cathode so that ions resulting from the maintenance gas flow through the aperture defined in the cathode before reaching the substrate; and

a second gas flow aperture or channel for enabling a depositing gas, different from the maintenance gas, to flow through the second gas flow aperture or channel and approach the aperture defined in the cathode from a side thereof opposite the first gas flow aperture or channel, so that the maintenance gas and the depositing gas approach the aperture defined in the cathode from opposite sides of the cathode.

18. The ion beam source ofclaim 17, wherein ions resulting from the depositing gas proceed toward the substrate without passing through the aperture defined in the cathode.

19. The ion beam source ofclaim 17, wherein the depositing gas approaches the aperture defined in the cathode from above the cathode, and the maintenance gas approaches the aperture defined in the cathode from below the cathode.

20. A method of ion beam depositing a layer on a substrate, the method comprising:

providing an ion source including a cathode, an anode located proximate an aperture defined in the cathode, and at least one magnet for generating a magnetic field proximate the aperture defined in the cathode, wherein an ion beam is emitted toward the substrate from an area in or proximate the aperture defined in the cathode;

causing a maintenance gas to flow by the anode and thereafter into the magnetic field proximate the aperture defined in the cathode so that ions resulting from the maintenance gas flow through the aperture defined in the cathode before reaching the substrate in the ion beam; and

causing a depositing gas, different from the maintenance gas, to approach the aperture defined in the cathode from an opposite side thereof, so that the maintenance gas and the depositing gas approach the aperture defined in the cathode from opposite sides of the cathode.

21. A method of ion beam depositing a layer on a substrate, the method comprising:

providing an ion source including a first electrode, a second electrode located proximate an aperture defined in the first electrode, and at least one magnet for generating a magnetic field proximate the aperture defined in the first electrode, wherein an ion beam is emitted toward the substrate from an area in or proximate the aperture defined in the first electrode;

causing a maintenance gas to flow by the second electrode and thereafter into the magnetic field proximate the aperture defined in the first electrode so that ions resulting from the maintenance gas flow through the aperture defined in the first electrode before reaching the substrate in the ion beam; and

causing a depositing gas, different from the maintenance gas, to approach the aperture defined in the first electrode from an opposite side thereof, so that the maintenance gas and the depositing gas approach the aperture defined in the first electrode from opposite sides thereof.

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